The rear sight is adjustable for elevation and windage, and the foresight can be adjusted for elevation for zeroing. The barrel has a built-in carry handle for ease of changing the barrel. The gun is gas operated, with a rotating bolt.

The weapon system was not designed for customization, due to the fact that most soldiers of the South Korean military will not see extended use of their weapons.

By 2015, ROK forces were looking to obtain a new LMG, as the K3 was suffering from age and reliability issues. S&T Motiv is attempting to get win the contract by modernizing the K3 with a side-folding adjustable stock, an integral MIL-STD-1913 rail on feed cover, detachable side and underside rails, a carbon fiber heat shield over barrel, an improved muzzle brake/flash hider, folding iron sights, and an upgraded feed system. The same improvements would also be applied to the shorter "Para" version.[3]

One example of the K3 was purchased by South Africa in 2006, and two examples were purchased by Thailand in the same year.[4] A controversy broke out 2007 in the Philippines when the country's Armed Forces initially selected the FN Minimi rather than picking the K3 or the 5.56 mm Ultimax from Singapore. The AFP's Modernization Program was attacked for showing favoritism towards a Western firearms company over Asian arms manufacturers.[5]

Ultimately, 6,540 K3s 5,883 K3s were acquired by the Philippine Army for their SAW requirement.[6] 5,883 units were first shown in public on February 18, 2008, together with 603 newly delivered Kia KM-450 trucks.[7]